P0175 means System Too Rich (Bank 2). A rich condition on bank 2. If P0172 is set too, look for a cause both banks share. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0175 means
The engine computer keeps adjusting fuel to hold the air-fuel mixture near the ideal ratio, using oxygen sensor feedback. Those adjustments are fuel trims: short-term trim reacts instantly and long-term trim learns over time. Positive numbers mean the computer is adding fuel; negative numbers mean it is taking fuel away. When long-term trim sits near the limit the computer allows, it sets a lean or rich code. On a V engine, bank 1 is the side containing cylinder 1 and bank 2 is the opposite side; inline engines only have bank 1.
P0175 symptoms
- Black smoke or a fuel smell
- Poor fuel economy
- Rough running
Common causes of P0175
- Leaking injector on bank 2
- High fuel pressure
- MAF or coolant temperature sensor errors (shared causes usually set both banks)
- Restricted air intake
How to diagnose P0175
- Check whether P0172 is also present
- Compare fuel trims between banks
- Test fuel pressure and look for leaking injectors
Can you drive with P0175?
As with P0172, drive only briefly and fix the cause before plugs foul or the converter overheats.
P0175 tips
Because shared faults usually set both banks, a P0175 without P0172 points toward something on bank 2 alone, most often a leaking injector. A fuel pressure gauge that loses pressure quickly after shutdown, or an injector balance test, helps confirm it.
Will P0175 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0175 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0172 | System Too Rich (Bank 1) |
| P0174 | System Too Lean (Bank 2) |
| P0101 | Mass or Volume Air Flow Circuit Range/Performance |
Guides that help
- fuel trim explained
- fuel pressure regulator
- fuel injector symptoms
- fuel pump, filter and regulator symptoms
- MAF sensor symptoms and cleaning
When it is more than a sensor
Fuel trim codes are almost always fixed with a leak repair, a sensor or a fuel delivery part. If a long-running lean condition has burned a valve or piston and a compression test confirms it, compare repair against a replacement on our engines page and see engine replacement cost.
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